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Patented July 9,1935 o. 2,007,241

PURIFICATION or MUSK-AMBRETTE Miles A. Dahlen, Wilmington, DeL, and Walter V..Wirth, Woodstown, N. J., assignors to E. I. du Pont de Nemours '& Company, Wilmington Bel., 'a corporation of Delaware 7 No Drawing. Application March 1, 1934, Serial v No. 713,522

13 Claims. (01. 260 -143) This invention relates-to the manufacture of cohol or benzene. The separation is therefore perfume chemicals; More. particularly; it reincomplete, and the loss of the valuable product lates to an improved process for the purification in the mother liquor is rather high. of musk-ambrette. I Zeide and Dubinin (ibid) have shown that 5 Musk-ambrette, an important, fixative in the musk-ambrette may be separated from dinjitroperfume art, is generally prepareclyby nitrating: methoxy-toluene by fractional distillation, since tertiary-butyl-B-methoxy-l-toluene. .The structhe former boils atl85 C. under. 16 mm. presture of the final compound is believed in the art sure while the; latter boils 202-3? C. under the rat oFFicE V to correspond to the following formula same conditions. This method, however, has the C disadvantage that the boiling point of dinitro- 10,

. H methoxy-tolueneis too high to allow it to be dis N V tilled in simple and economically operated dis-,

: V tillation equipment. It may be left as astill OOHa residue, but if it is desired as an intermediate C(GHm through special purification steps. V Now, according to our improved process, we separate the muskeambrette from its by-products by subjecting the crude mass to an extraction treatment with an organic liquid. We found that 20 vliquidnon-aromatic hydrocarbons, such as the parailins, olefines, and cycloparafiins form ex.- I H i cellent solvents formusk-ambrette, while being V substantially non-solvents for dinitro-B-methoxyetoluene. The eifect is rather surprising in view of the fact that solid aromatic nitrol como pounds in general are notorious'for their poor solubility in aliphatic hydrocarbons. It was N02 'thereiore'not to be expected that non-aromatic in considerable amounts, the butyl vgroup behydrocarbons could be found whose solubility 30 ing replaced by a nitro group. Small quantities for the two main. constituents of the nitration of mono nitro compounds and oxidation products p du herein Considered Would differ S Widely are also formed in the nitration processes. .7 s to afford a m an f p r n y h mp 4,6-dinitro-3-methoxy-toluene is a pale yellow p oce s Of eXtra'ctionf l (2,6-dinitro-4-tert-butyl 3 -methoXy'-toluene; Zeide and Dubinin, Jour. of Gen. Chern. U. S S.'R.-vol. 2,.pa es' 455 471. 1

During. the nitration, however, there is also formed 4,6-dinitro-3-methoxyto1uene.

crystalline solid, melting at 101 C.. Extraction differs'from fractional crystallize 35 The present application i v concerned with 2. tion in that the entirecrude mass does not have, process for separating the nitration mass into to beb ought in So ut n p o & a fl i n its components, whereby to obtain each. ofthe ur extra ti n p ss a -quality soluti n of two main constituents in a highly pureform,and musk-ambretta' on the one hand, and substan substantially free of the other constituent. .It ti ly p B h0Xy-toluene, on the other 40 is a further object of this invention to improve hand, are Obt in One p by merely ag a th economy f the, separation process. Other ing the crude solid mass with a'solvent as above and-further important objects of invention mentioned; In fractional crystallization, howfwill appear as the description proceeds. ever, complete solution of the crude mass-is necesw According'to the methods previously described sary first. From this, the bulk of musk-ambrette for the isolation and ipmification 'of .muskeamis crystallized out; the mother liquor, however, brette', the crude nitration product was ,subcontains a mixture of residual musk-ambrette and jected to fractional crystallizationfromyalcohol the debutylated by-product whioh can be sepor benzene. Such .ayprocedure isgdescribed by arated from each other only by further, laborious Knoll and Wagner on'page' 22,7; of Synthetische procedures. 7 und lsolierte Riechstoffe =(Zweite, Auflaige, Ver Accordingly, mp v M 338 consists of lag vom.Wi'lhelrn,Knap.p) Ha1le,lGermany,1928. agitating-the filtered nitration mass with a non- This process,,however, suifers from the drawaromatic hydrocarbon, for instance petroleurn back thatboth .muskwambrette and dinitronaphtha, in quantity sufficient to dissolve the 4 ,rnethoxy-toluene are, highly soluble in; either almuslcambrette present in the mixture. The so for other useful compounds, it must be put '15,

dinitro-methoxy-toluene mostly stays behind as a solid, and only a very small quantity thereof goes into solution. The bulk of the dinitro-methoxy-toluene may, therefore, be removed by filtration, and washed in the usual manner, whereby it is obtained in a state of purity suflicient for most practical purposes.

The mother liquor is then either concentrated to crystallize out musk-ambrette in a high state of purity, or evaporated to dryness. In the latter case the residue still contains small quantities of dinitronethoxy-toluene and other by-prodnets of the nitration. It may be purified finally by any suitable procedure, such as distillation, or recrystallization from alcohol, benzene, or an aliphatic hydrocarbon. Since the dinitro-methoxy-toluene content of this residue is very.

small, the crystallization may be carried out in very concentrated solution and the loss of material inthe filtrate is very small.

Without limiting our invention to any particular procedure, the following examples, in which parts by weight are given, will serve to illustrate our preferred mode of operation.

Example I 243 parts of the solid nitration mass obtained in the nitration of tertiary-butyl-B-methoxy-l-toluene, (for instance by the aid of fuming nitric acid in a medium of acetic anhydride) were added to 1000 parts of petroleum naphtha, having a boiling range of 70 to 100 C. The mass was heated, and stirred at 70 C. for about /2 hour. The mass was then cooled to 40 C., filtered, and the filter 1 cake washed with 50 parts of naphtha.

The filter cake, constituting substantially pure dinitro-3-methoxy-l-toluene, was dried at C. The yield was 47 .5 parts, and its melting point was 96 to 98 C.

The mother liquor was heated to C. to boil ofi the naphtha, first at atmospheric pressure and then at 50-60 mm. of mercury, absolute. The residue contained 196 parts of musk-ambrette, melting at 80 C.

This material was then crystallized twice from alcohol to give a product melting at 85 C.

From the mother liquors of the alcohol crystallization further quantities of musk-ambrette may be recovered by evaporation, and adding the mixed residue to a subsequent batch of the nitration product to be fractionated.

Example II The procedure of Example I was followed down to the point where the dinitro-methoxy-toluene was removed by filtration, and the mother liquor evaporated to give 196 parts of crude musk-ambrette. This product was then fractionally distilled under an absolute pressure of about 2 mm. The musk-ambrette distilled over at 137 to 139 C. About 183 parts of musk were obtained, melting at 82 C. This was crystallized once from 455 parts of alcohol, and gave a product melting at 85 C.

Example III A suitable kettle was charged with 425 parts of cyclohexane and parts of dry crude musk, that is, the crude mixture of solids as obtained in the nitration of tert-butyl-3-methoxy-l-toluene. The charge was heated to 70 C. and stirred at this temperature for about hour. The temperature was then lowered to 40 C. and the un dissolved 2,6-dinitro-3-methoxy-toluene was separated from the musk solution in a centrifuge as described in Example I. The process of this example was then followed, giving essentially the same results as recorded above.

It will be understood that the process is subject to variations in the nature and amount of the extracting liquid used, temperatures involved, etc. Thus, instead of petroleum naphtha, any other light petroleum fraction, for instance kerosene or ligroin, may be employed; or again, any individual non-aromatic hydrocarbon or mixture of such hydrocarbons may be used, for instance, the liqquid members of the parafline family (hexane, heptane, octane, etc.) the aliphatic unsaturated hydrocarbons (hexene, heptene, octene, nexa diene, octine, etc.) or the cycloparafiines (cyclohexane, methyl-cyclohexane, methyl-cyoloheptane, cyclohexene, decalin, etc.)

'The musk-ambrette can be crystallized directly from the naphtha solution and then from alcohol or any other suitable solvent. The naphtha can be removed'from the naphtha-musk solution by steam distillation and the residual musk can be distilled over with superheated steam, before final crystallization from a suitable solvent.

Many other variations and modifications will be apparent to those skilled in the art.

It will be clear now that our process provides an improved and efficient method for separating the constituents obtained in the nitration of tertiary-butyl-S-methoxy-l-toluene, and possesses the following advantages over the prior practice.

1. An almost complete recovery of the pure musk may be effected in a simple manner, whereas according to the prior art, large losses of musk are incurred.

2. The by-product dinitro-3-methoxy-l-toluene may be recovered readily and in good purity.

3. Very cheap hydrocarbon solvents-such as petroleum fractionsmay be used for the preliminary separation of musk from dinitro-3-methoxy-l-toluene.

4. The separation and purification operations are readily carried out in simple equipment, and the recovery of solvents is likewise readily effected.

,5. The cost of separating and purifying the 1. The process for recovering musk-ambrette from the crude nitration mass in which it is formed, which comprises subjecting the crude solid mass to extraction by means of a solvent consisting predominantly of a non-aromatic liquid hydrocarbon.

2. The process for recovering musk-ambrette from the crude nitration mass in which it is formed, which comprises subjecting the crude solid mass to extraction by means of a solvent consisting predominantly of liquid hydrocarbons or the group consisting of the parafiins, cycloparafiins, and unsaturated aliphatic hydrocarbons.

3. A process for separating dinitro-3-methoxyl-toluene and musk-ambrette from a mixture containing the two, which comprises extracting the solid mixture by the aid of a solvent comprising as a major ingredient an aliphatic liquid hydrocarbon.

4. A process for separating dinitro-3-methoxyl-toluene and musk-ambrette from a mixture containing the two, which comprises heating the mixture in a liquid aliphatic hydrocarbon to dissolve the musk-ambrette, and separating the insoluble dinitro-3-methoxy-1-toluene.

5. A process for recovering musk-ambrette from the solid nitration massobtained by nitrating tertiary-buty1-3-methoxy-l-toluene, which,

comprises heating said nitration mass in a liquid petroleum fraction until the musk has gone into solution, filtering off the insoluble residue, and recovering musk-ambrette from the mother liquor. 1

6. A process for recovering musk-ambrette from thesolid nitration mass obtained. by nitrating tertiary-butyl-Bemethoxy-1-toluene, which comprises heating said nitration mass in a liquid petroleum fraction until the musk has gone into solution, filtering off the insoluble residue, and concentrating the mother liquor to crystallize out musk-ambrette.

7. A process for recovering musk-ambrette from the solid nitration mass obtained by nitrating tertiary-butyl-3-methoxy-l-toluene, which comprises heating said nitration mass in, a liquid petroleum fraction until the musk has gone into solution, filtering off the insoluble residue,

and evaporating the mother liquor to dryness.

8. A process for recovering musk-ambrette from the solid nitration mass obtained by nitrating tertiary-butyl-3-methoxy-l-toluene, which comprises'heating said nitration mass in a liquid petroleum fraction until the musk has gone into solution, filtering oil the insoluble residue, evaporating the motherliquor to dryness, and subjecting the residue thus obtained to further purification. t

9. A process for recovering musk-ambrette from the solid nitration mass obtained by nitrating tertiary-butyl-B-methoxy-l toluene, which comprises heating. said nitration mass in a liquid petroleum fraction until thelmusk has gone into solution, filteringofi the insoluble residue, evaporating the mother liquor to drynessand subjecting the residue thus obtained to fractional distillation under a vacuum.

10. A process for recovering; musk-ambrett'e from the solid nitration mass obtained by nitrat-,

ing tertiary-butyl-B-methoxy-l toluene, which comprises heating said nitration mass in a liquid petroleum fraction until the musk has gone into solution, filtering off the insoluble residue, evaporating the mother liquor to dryness, and subjecting the residue thus obtained to recrystallization from a solvent.

11. The process of recovering musk-ambrette from the mixture of nitration products obtainable by reacting With fuming nitric acid in the presence of acetic anhydride upon tertiary-butyl- 3-methoXy-1-toluene, which comprises heating tially near the boiling point, filtering oiT the undissolved residue, evaporating the mother liquor to dryness, and subjecting the residue thus obtained to recrystallization from alcohol.

13. The process of recovering musk-ambrette' from the mixture of nitration products obtainable by reacting with :fuming nitric acid in the presence of acetic anhydride upon tertiary-butyl- 3-methoxy-l-toluene, which comprises heating the mixture of solids obtained in said nitration in petroleum naphtha to a temperature substantially near the boiling point, filtering ofi the undissolved residue, evaporating the mother liquor to dryness, subjecting the residue thus obtained to fractional distillation under a vacuum, and collecting the fraction boiling at 137 to 139 C. under-an absolute pressure of 2 mm.

* MILES A; DAHLEN.

' WALTER V. WIRTI-I. 

